Geomorphology of La Pedriza granitic massif, Guadarrama Range

Abstract

The Pedriza de Manzanares, located in the Guadarrama Range, Iberian Central System, is a Variscan massif formed by I-type peraluminous leucogranites intruded in the late Paleozoic (~307 ma). The morphostructure of the massif is largely the result of the reactivation of faults during the Alpine Orogeny (Paleogene–Pliocene) and the associated etching/exhumation processes. The former produced a stair-stepped topography (block faulting), and the latter gave rise to granitic domes and crests related to differential erosion. The domes, and to a lesser extent the crests with tors and widespread chaotic blocks, are the essential features of the landscape in the Pedriza de Manzanares. The low chemical weathering susceptibility of the granites in this area, together with the fracture system, favour the development of structural landforms. Moreover, on bare rock exposures, minor landforms formed by diverse weathering processes are frequent.